Multiconductor cable and method of forming the same



W. D. KELLY MULTICONDUCTOR CABLE AND METHOD OF FORMING THE SAME Jan. 14, 1969 Filed March 14, 1968 United States Patent Ofiice 3,422,214 Patented Jan. 14, 1969 3 422,214 MULTICONDUCTOR CABLE AND METHOD OF FORMING THE SAME William D. Kelly, 12 Blodgett St.,

. Clarendon Hills, Ill. 60514 Filed Mar. 14, 1968, Ser. No. 713,098 US. Cl. 174-103 Int. Cl. H0111 7/18 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to metal sheathed or metal clad electrical conductors.

It is the general object of the present invention to produce a new and improved metal clad wire of the character described.

It is a further object of the invention to produce a new and novel method of encasing a plurality of insulated electrical wires within a metal sheath Without the necessity of welding the sheath in order to retain the same in interlocking relation to the wires.

The metal sheathed conductor of the present invention is a form of, but an improvement upon, the metal sheathed conductor shown in my United States Letters Patent No. 3,206,539. One form of improvement over the shape shown in said basic Patent No. 3,206,539, is shown in my copending application Ser. No. 672,281 filed Oct. 2, 1967 (now US. Patent No. 3,404,217). The present improvement in the metal clad or metal sheathed conductor and the method of forming the same over that shown in my Patent No. 3,206,539 will be readily apparent from the following description and drawings, in which:

FIG. 1 is an enlarged sectional view showing the completed metal clad electrical conductors;

FIG. 2 shows a portion of a strip of sheet metal dur ing the initial stages of forming the completed item;

FIGS. 3, 4, 5 and 6 are views like FIG. 2 showing succeeding steps in the formation of the completed product.

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a specific embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

Referring now to FIGS. 2-6 of the drawings, it will be seen that there is provided a strip of sheet metal 10 having spaced parallel lines of weakness in the form of notches 11 and 12 formed on opposite sides of the strip in the central portion 13 thereof. Two insulated electrical wires 14 and 15 are positioned in a die cavity, so as to hold them in position as the strip and wires, technically endless, are fed through die means for performing the bending and folding operations hereinafter to be described. The next operation is to fold the strip approximately 90 degrees in opposite directions along areas adjacent but spaced from the central portion 13 as illustrated in FIGS. 3 and 4. This is preferably a two-step operation to provide the sharpness of curves shown and leaving the central portion 13 in the form of an upstanding web. The edges of the strip are then bent outwardly to form the peripheral ledges 16 and 17 shown in FIG. 5, following which the porti-ons 18 and 19 of the strip intermediate the central portion 13 and the peripheral ledges are rolled inwardly in opposite directions to encase the wires as shown in FIG. 6.

At this time, inward pressure is exerted upon opposite sides of the strip in the form found in FIG. 6 as indicated by the arrows 20 and 21 in FIG. 1, while maintaining the assembly against vertical elongation or bending by means of pressure applied in the areas and in the directions indicated by the arrows 22 and 23. The result is to form the central portion 13 into a general 3 shape, with the corners of the S being at the location of the lines of Weakness 11 and 12. The peripheral ledges are thus locked against the outer faces of the top and bottom of the and the adjacent portions of the strip, thereby forming an interlock retaining the assembly in the folded configuration shown in FIG. 1 and encasing the wires 14 and 15 within the intermediate portions 18 and 19.

The resulting assembly serves firmly to retain the wires encased within the strip of sheet metal folded as shown and described, and presents a relatively water-tight assembly and yet one which can be easily bent in any direction, thereby facilitating its use as an electrical conduit over other forms of metal clad wires.

I claim:

1. The method of forming a metal clad electrical conductor which comprises, afiixing a pair of insulated wires in spaced parallel relationship longitudinally of a strip of sheet metal, forming a pair of spaced parallel lines of weakness on the central portion of said strip, said lines being on opposite sides of the strip and between said wires, forming approximately -degree bends longitudinally of the strip on adjacent sides of the central portion, forming peripheral ledges along the outer edges of the strip, rolling the outer portions of the strip in opposite directions inwardly toward the central portion to enclose the wires, and then applying pressure inwardly from the outer sides of the rolled portions to cause the central portion to bend at the lines of weakness into generally the shape of a S with the ledges locked against the outer faces of the top and bottom of the S.

2. The method of claim 1 in which a restraining pressure is applied to the top and bottom of the assembly during the application of said inwardly applied pressure.

3. A metal clad conductor comprising, a pair of spaced insulated electrical wires encased within a single strip of sheet metal, the intermediate portion of said strip of sheet rnetal being bent into the form of a S with the inner corners ofthe 2 being located by lines of longitudinally extending spaced parallel lines of weakness in said central portion, and with the edges of the strip being locked into position against the outer faces of said X shaped central portion.

References Cited UNITED STATES PATENTS 1,840,536 l/1932 Shore 174-103 X 1,949,077 2/1934 Kalischer 174-103 3,206,539 9/1965 Kelly 174-68 LARAMIE E. ASKIN, Primary Examiner.

US. Cl. X.R. 

